Learning jQuery, Third Edition [Paperback]

Chapter 1: Getting Started

The book starts off with a quick introduction to jQuery, what it does and why it works so well. As the authors point out one of the great things you learn about jQuery right away is that it abstracts away browser quirks for you. With most browsers putting out a new version every few months this becomes a solid benefit for using jQuery.

The chapter includes an example (the HTML in the sample has been updated to HTML5) to inject a new CSS class to a particular DIV on the page. They demonstrate how this could be done without jQuery using plain JavaScript so you can see how much time jQuery saves you in terms of the amount of code you would need to write otherwise.

The chapter finishes off with a quick mention and demo (using Firebug) of some tools you can use to help work with jQuery more efficiently when your writing code.

Chapter 2: Selecting Elements

The basics are laid out in this chapter like the DOM and how HTML pages are structured, the $() function, CSS selectors and custom selectors. Each topic is shown either in code or an image to better represent it to the reader. The code examples are easy yet practical and even a beginner in HTML/JavaScript shouldn't have much of a problem following along. The sub-topics in the chapter are then used to introduce things like DOM traversal methods (their example of styling specific cells is useful), chaining, and ends off with accessing DOM elements.

Chapter 3: Handling Events

Towards the start of this chapter there is a good hint they mention regarding putting your style tags before the script tags in your HTML page, that way you know your page has been styled before any script has been run. This might be common sense to an experienced developer but to a new jQuery developer it is an excellent learning tip - one of the many hints throughout the book that will help you along and better understand not just jQuery but HTML/CSS/JavaScript as well.

This chapter does a good job of explaining and demoing events as well as how you can get jQuery and other JavaScript frameworks to play together nicely using jQuery.noConflict. Simple events are covered and then the authors move onto compound events all with real world demonstrations and code. This really is a great chapter and is packed with information like simulating user interaction, event bubbling, etc.

Chapter 4: Styling and Animating

This is probably the most fun chapter to read and work through the demos. You learn how to do animations (including custom ones) and effects. All the basics are here and are followed up with good demos and source code. In addition they show how to animate multiple properties at once (perhaps you want to use a slide and a fade effect together), simultaneous versus queued effect and ending off with working with multiple sets of elements.

Chapter 5: Manipulating the DOM

This chapter starts to get much more technical where you start to dive into doing heavier modifications like manipulating attributes (attr() and .removeAttr(), etc), creating/inserting/copying elements. Fortunately, the demos are great and present the content in a readable fashion that makes sense. This is a shorter chapter than some of the others but is packed with a lot of information. You might need to read it more than once to fully grasp it all if your new to jQuery.

Chapter 6: Sending Data with Ajax

Ah, AJAX! Perhaps one of the most discussed topics in jQuery books and articles for the past several years. No jQuery book would be complete without a discussion of the excellent support jQuery offers for AJAX. A simple example kicks off the chapter followed by loading JSON and XML content. Passing data to the server they show their demonstration and code using server-side PHP.

The section on Serializing a Form I think was good with the simple example they used but I do feel it should have followed up with a more real world example that was a bit more complex (using more then one form element, ex: using combo boxes, multiple textboxes, radio buttons, etc.).

The section Keeping an eye on the request is useful and shows you how to display a "loading" message wile your AJAX request is loading. They also show how to handle errors as well as security limitations which naturally leads right into a discussion of JSONP (JSON with Padding). The example is good and the typical warning on using JSONP is pointed out. The chapter ends with diving into the low-level Ajax method.

Chapters 7 and 8: Using Plugins and Developing Plugins

Both of these chapters are dealing with either using plugins or developing you own. Chapter 7 starts you off with locating, installing and using plugins. It ends off with one of the most useful plugin libraries available to jQuery which is jQuery UI. Also, as the book points out the jQuery UI library is really a set of plugins - you can pick and choose which ones you want in your project or take them all.

Chapter 8 goes over the types of plugins you can create and shows how to build each one. Both chapters give you enough to get started with plugins in general, at least to craft a simple to moderately difficult plugin. Its all the essential information you need if you do see yourself writing plugins in the future for jQuery.

Chapters 9, 10, 11, 12, 13

The final chapters in the book cover the initial topics but now dive deeper into them. Advanced Selectors and Transversing, Advanced Events, Advanced DOM Manipulation and Advanced AJAX are all covered and elaborated on.

This is an interesting way to split the book up with a great jQuery introduction at the start of the book and then diving deeper on each topic at the end of the book. Someone already familiar with jQuery could skip to the first half of the book when they feel they need more than just the basics. The same is true if your an expert in say AJAX but need to learn the basics of using plugins, etc. It makes for a great reference and a logical split of the basic information and the more advanced.

There are three appendixes as well: JavaScript Closures (a must read and the authors did a good job in simplifying a topic some developers can find difficult at first). Testing JavaScript with QUnit (used for functional testing and unit testing) and a quick reference make up the final parts of the book. QUnit is a very good tool for testing and it's nice that they included it in the book.

All-in-all this is a good book to learn jQuery with no fluff.

jQuery is a powerful enhancement of JavaScript, whose full scope is attested to by Chaffer and Swedberg. If you find yourself needing to write dynamic HTML pages, then JavaScript will also certainly be the choice of language. Yet the book explains that CSS is another necessity. While the still persistent differences between browsers in how they display web pages is an unfortunate reality of the marketplace. This can lead to spaghetti code of if-then ladders, that try to search for and have specific code for each major browser. The result is code bloat, with oft-unreadable logic, where the sheer mass of source acts against understanding.

For both these reasons, the text delves into how jQuery can help. Other reasons are also present. The overall point of the book is that jQuery lets you have concise code, where you can deprecate tangled details. For pedagogic reasons, the book starts right away with an example implemented in jQuery and then in vanilla JavaScript. The former code snippet is impressively short, while the latter is clear enough, but much longer. If you are experienced in programming in any other language, you can appreciate the multiple coding advantages of the former. The shorter length of code is less error prone, and much easier to follow the logic.

The book is also a good workout for understanding and manipulating the Document Object Model, where you can understand how this mediates between a web page and JavaScript. This is done in tandem with using CSS to control in a refactorable manner the final look of the page. An entire chapter (#5) is devoted to showing how jQuery can move around a DOM in very flexible ways. Standard explanations of a DOM give off that it is largely a static representation of a page. Yet the chapter can change your outlook. jQuery can embed sophisticated logic to produce a very dynamic DOM and final page.

The discussion on Ajax was also important enough to warrant an entire chapter. jQuery can readily access a JSON structure.

Of course, for the above important cases, the abilities of jQuery to interact are no accident. Behind the current version of jQuery is a substantial feedback loop, where developers of jQuery have explicitly modified the language to make exactly the current state.